This document describes how to use the PAD built by RAD. We use the APD-2 in a special configuration for the Austrian Federal Railways ÖBB. The ÖBB X25 protocol is described in the "ÖBB X25 Pflichtenheft". This protocol specifies the Layer 4 to 7 for vital and not-vital comunication between railway-station equipment (e. q. interlocking, etc.). The ÖBB X25 protocol specification uses the CCITT X.25 / X.21 communication and uses PVC 1 for channel A and PVC 2 for channel B transmission.
The two-channel transmission in channel A and channel B is used for raising the safety of the connection. In channel B the data is transmitted inverted. For more details cunsult the "ÖBB X25 Pflichtenheft".
Special thanks to Ing. Johann Berger <j.berger@online.edvg.co.at> for the help on getting the first APD-2 and a complete X.25 testconfiguration with Datus-PADs and X.25 Modems (Nokia SB64 and Siemens DAG64 types).
For details to the ÖBB X25 specification you should contact Johann Berger.
Thanks to Michael Smutka <michael.smutka@teleweb.at> for his ideas and reviewing this document and the code.
If you have any suggestions to this document, than feel free to contact me:
Have a lot of fun with this easy to use, easy to configure and very small X.25 PAD APD-2 from RAD.
For testing the configuration in this document I used the following testequipment:
+-------+ +-------+
| |-| |
ch. A -----| |V|MIC-24T| +-----+
| APD-2 |2| /21C |-----|Modem|~~~~~~~~~~~~~~~+
ch. B -----| |4| | +-----+ |
| |-| | |
+-------+ +-------+ 2-wire |
longdistance|
+-------------+ connection |
| | |
ch. A -----| | +-----+ |
| Datus-PAD |---------|Modem|~~~~~~~~~~~~~~~+
ch. B -----| | +-----+
| |
+-------------+
APD-2 ........ PAD with two V.24(8pin-RJ45)/X.28 connectors
and one V.24(25pin-SUB-D)/X.25 connector
manufactored: RAD
MIC-24T/21C .. Converter V.24(25pin-SUB-D) to
X.21(15pin-SUB-D) connector
manufactored: RAD
Modem ........ X.21 Modem with 64 kBit/sec
e.q.: Nokia SB 64k
or
Siemens DAG 64
Datus-PAD .... 5820 with 2 V.24 connectors and 1 X.21
connector
On channel A and B on both ends of the testconfiguration (Datus-PAD and APD-2) we connected the Testrechner TR application, which you also can find on my homepage. You may use any other applications with V.24 connection with 19.200 baud, no parity, 8 Bit, 1 Stopbit.